The proposed research is designed to gain an understanding of the way in which complex vibrotactile patterns are processed by the skin. The project will examine a number of ways of presenting vibratory patterns to the fingertip using the Optacon, a reading aid for the blind. The patterns will be letters of the alphabet. The ability of observers to recognize letters, presented in various ways, will be measured. Sighted observers, who may be particularly good at vibratory pattern recognition tasks, will be tested for their ability to read rapidly through their fingertips. Measurements are also planned on masking of letters presented through the Optacon. The effects of changing the intensity of the masking stimulus, the time between the masking stimulus and the test signal, and the duration of the test signal will be measured. Conditions which affect the amount of vibrotactile spatial summation will also be examined.